In the flotation process, the concentrate grade and the tailing grade are crucial technical indices which reflect the product quality and efficiency. There are strong nonlinearity and uncertainty in such technical indices dynamic behaviors, which can hardly be described using accurate mathematical model. The technical indices which cannot be measured online continuously vary with boundary condi...

Extended tailing of low bacterial concentrations following breakthrough at the Narrow Channel focus area was observed for 4 months. Bacterial attachment and detachment kinetics associated with breakthrough and extended tailing were determined by fitting a one-dimensional transport model to the field breakthrough-tailing data. Spatial variations in attachment rate coefficient (k f) were observed...

Self-ignited, naturally occurring coal fires and fires resulting from human activities persist for decades in underground coal mines, coal waste piles, and unmined coal beds. These uncontrolled coal fires occur in all coal-bearing parts of the world (Stracher, 2007) and pose multiple threats to the global environment because they emit greenhouse gases—carbon dioxide (CO2), and methane (CH4)—as ...

Small silencing RNAs, including microRNAs, endogenous small interfering RNAs (endo-siRNAs) and Piwi-interacting RNAs (piRNAs), have been shown to play important roles in fine-tuning gene expression, defending virus and controlling transposons. Loss of small silencing RNAs or components in their pathways often leads to severe developmental defects, including lethality and sterility. Recently, no...

BACKGROUND Particulate exposure from air pollution increases the risk of ischemic heart disease (IHD) mortality. Although coal miners are highly exposed to coal dust particulate, studies of IHD mortality risk among coal miners have had inconsistent results. Previous studies may have been biased by the healthy worker effect. METHODS We examined the dose-response relationship between cumulative...

There are many coal seams in high-gas mining area of China. The permeability is low. The gas extraction from the original coal seam is difficult and the commercial value is little. The conception of the safe high-efficient exploitation of coal and gas is put forward in this article. It changes the conventional exploitation sequence that is from the upper to below. When we exploit coal seams, th...

Pulverized Wyoming subbituminous coal was beneficiated by low-pH oil agglomerationat CONSOL to prepare the coal for direct liquefaction. Conventional cleaning is not veryeffective in cleaning this coal; for example, conventional oil agglomeration only givesabout 20% ash rejection. To improve ash rejection, the coal-water slurry was acidifiedto a pH of about 0.5. Oil agglomeratio...

OBJECTIVE To estimate the risk of lung cancer associated with the use of different types of coal for household cooking and heating. SETTING Xuanwei County, Yunnan Province, China. DESIGN Retrospective cohort study (follow-up 1976-96) comparing mortality from lung cancer between lifelong users of "smoky coal" (bituminous) and "smokeless coal" (anthracite). PARTICIPANTS 27,310 individuals u...